Polymeric dispersants having polyalkylene and succinic groups

ABSTRACT

Novel copolymers of unsaturated acidic reactants and high molecular weight olefins are useful as dispersants in lubricating oils and fuels and also may be used to prepare polysuccinimides and other post-treated additives useful in lubricating oils and fuels. The ratio of anhydride groups to the hydrocarbon groups in these novel copolymers is at least 1.3.

This is a continuation of application Ser. No. 08/469,736, filed Jun. 6,1995, now abandoned, which in turn is a continuation of Ser. No.08/165,871 filed Dec. 13, 1993, now abandoned.

The present invention relates to compositions that are useful asintermediates for dispersants used in lubricating oil compositions or asdispersants themselves. In addition, some of these compositions areuseful in the preparation of novel high molecular weight dispersantsthat have superior dispersant properties for dispersing sludge andvarnish and superior Viton Seal compatibility.

The high molecular weight dispersants of the present invention alsoadvantageously impart fluidity modifying properties to lubricating oilcompositions sufficient to allow elimination of some proportion ofviscosity index improver from multigrade lubricating oil compositionsthat contain these dispersants.

BACKGROUND OF THE INVENTION

Alkenyl-substituted succinic anhydrides have been used as dispersants.Such alkenyl-substituted succinic anhydrides have been prepared byvarious processes, including a thermal process (see, e.g., U.S. Pat. No.3,361,673) and a chlorination process (see, e.g., U.S. Pat. No.3,172,892). The polyisobutenyl succinic anhydride ("PIBSA") produced bythe thermal process has been characterized as a monomer containing adouble bond in the product. Although the exact structure of chlorinationPIBSA has not been definitively determined, the chlorination processPIBSAs have been characterized as monomers containing either a doublebond, a ring, other than a succinic anhydride ring and/or chlorine inthe product. [See J. Weill and B. Sillion, "Reaction of ChlorinatedPolyisobutene with Maleic Anhydride: Mechanism Catalysis byDichloromaleic Anhydride," Revue de I 'Institut Francais du Petrole,Vol. 40, No. 1, pp. 77-89 (January-February, 1985).] Such compositionsinclude one-to-one monomeric adducts (see, e.g., U.S. Pat. Nos.3,219,666; 3,381,022) as well as adducts having polyalkenyl-derivedsubstituents adducted with at least 1.3 succinic groups perpolyalkenyl-derived substituent (see, e.g., U.S. Pat. No. 4,234,435).

In addition, copolymers of maleic anhydrides and some aliphaticalpha-olefins have been prepared. The polymers so produced were usefulfor a variety of purposes, including dispersants for pigments andintermediates in the preparation of polyesters by their reaction withpolyols or polyepoxides. However, olefins having more than about 30carbon atoms were found to be relatively unreactive. (See, e.g., U.S.Pat. Nos. 3,461,108; 3,560,455; 3,560,456; 3,560,457; 3,580,893;3,706,704; 3,729,450; and 3,729,451).

U.S. Pat. No. 5,112,507 shows copolymers of unsaturated acidic reactantsand high molecular weight olefins that are useful as dispersants inlubricating oils and fuels and as intermediates in the preparation ofpolysuccinimide additives that give excellent deposit control. The ratioof anhydride groups to the hydrocarbon groups in those copolymers isgenerally 1.0.

SUMMARY OF THE INVENTION

The present invention is a copolymer of an unsaturated acidic reactantand a high molecular weight olefin, the copolymer having a ratio ofanhydride groups to the hydrocarbon groups that is at least 1.3.Preferably, the ratio of anhydride groups to the hydrocarbon groups isbetween 1.3 and 2.0. The copolymer can be formed by reacting the highmolecular weight olefin and the unsaturated acidic reactant in thepresence of a free radical initiator.

These copolymers are useful as dispersants themselves and also asintermediates in the preparation of other dispersant additives havingimproved dispersancy and/or detergency properties when employed in alubricating oil. They do not contain double bonds, rings, other thansuccinic anhydride rings, or chlorine (in contrast to thermal andchlorination PIBSAs) and as such have improved stability, as well asimproved environmental properties due to the absence of chlorine.

Preferably, the unsaturated acidic reactant is of the formula: ##STR1##wherein X and X' are each independently selected from the groupconsisting of --OH, --Cl, --O--lower alkyl and when taken together, Xand X' are --O--. More preferably, the acidic reactant comprises maleicanhydride.

The high molecular weight olefin has a sufficient number of carbon atomssuch that the resulting copolymer is soluble in lubricating oil. Theolefin can be an alpha olefin or an alkylvinylidene olefin. Preferably,the high molecular weight olefin is a high molecular weightalkylvinylidene olefin. More preferably, the olefin has at least 1branch per 2 carbon atoms along the chain. Most preferably, the olefinis polyisobutene having an average molecular weight of 500 to 5000 (morepreferably from 900 to 2500), and the alkylvinylidene isomer ismethylvinylidene.

In one embodiment, the copolymer has the formula: ##STR2## wherein n is1 or greater; either R₁ and R₂ are hydrogen and one of R₃ and R₄ islower alkyl and the other is high molecular weight polyalkyl, or R₃ andR₄ are hydrogen and one of R₁ and R₂ is lower alkyl and the other ishigh molecular weight polyalkyl; and wherein x and y are 1 or greater,such that the sum of x is at least 1.3 times the sum of y for the totalmixture. Preferably, the high molecular weight polyalkyl comprises apolyisobutyl group of at least about 50 carbon atoms and the lower alkylis methyl.

The present invention is also directed to polysuccinimides that areprepared by reacting a copolymer of the present invention with apolyamine having at least one basic nitrogen atom to give apolysuccinimide. Preferably, the polyamine has the formula H₂ N(YNH)_(p)H wherein Y is alkylene of 2 to 6 carbon atoms and p is an integer from1 to 6. Preferably, the charge mole ratio of polyamine to succinicgroups in copolymer is from about 1 to about 0.1. The polysuccinimidecan be reacted with a cyclic carbonate or with a boron compound.

Since the copolymers of the present invention contain greater than 1.3anhydride groups per hydrocarbon groups, polysuccinimides made fromthese will contain a higher concentration of nitrogen than dispersantsmade with one anhydride group per hydrocarbon group. This may beadvantageous, for example, in controlling engine deposits in automobileengines, or in dispersing soot in diesel engines.

However, in general, dispersants containing higher nitrogen levels aremore aggressive towards Viton seals, for example in the VW 3334 test. Wehave surprisingly found that the polysuccinimides of the presentinvention perform better in the VW 3334 test than the other dispersantsexamined, especially at the equal nitrogen level.

In addition the copolymers and polysuccinimides of the present inventioncontain little if any chlorine (less than 50 ppm). Thus these productsare preferable to use from an environmental point of view.

In addition, the present invention is directed to modifiedpolysuccinimides wherein one or more of the nitrogens of the polyaminecomponent is substituted with a hydrocarbyl oxycarbonyl, ahydroxyhydrocarbyl oxycarbonyl or a hydroxypoly(oxyalkylene)-oxycarbonyl. These modified polysuccinimides areimproved dispersants and/or detergents for use in fuels or oils.

Accordingly, the present invention also relates to a lubricating oilcomposition comprising a major amount of an oil of lubricating viscosityand an amount of a copolymer, polysuccinimide or modified succinimideadditive of the present invention sufficient to provide dispersancyand/or detergency. The additives of the present invention may also beformulated in lubricating oil concentrates which comprise from about 90to about 50 weight percent of an oil of lubricating viscosity and fromabout 10 to about 50 weight percent of an additive of the presentinvention.

Another composition aspect of the present invention is a fuelcomposition comprising a major portion of a fuel boiling in a gasolineor diesel range and from about 30 to about 5000 parts per million ofcopolymer, polysuccinimide or modified succinimide additives. Thepresent invention is also directed to fuel concentrates comprising aninert stable oleophilic organic solvent boiling in the range of about150° F. to about 400° F. and from about 5 to about 50 weight percent ofan additive of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to assist the understanding of this invention, reference willnow be made to the appended drawings. The drawings are exemplary only,and should not be construed as limiting the invention.

FIG. 1 shows a plot of tensile strength versus calculated ppm N forpolysuccinimides with 1300 MW tail.

FIG. 2 shows a plot of tensile strength versus calculated ppm N forpolysuccinimides with 2400 MW tail.

DETAILED DESCRIPTION OF THE INVENTION

In its broadest aspect, the present invention encompasses a copolymer ofan unsaturated acidic reactant and a high molecular weight olefin,wherein the ratio of anhydride groups to the hydrocarbon groups is atleast 1.3. The olefin can be an alpha olefin or alkylvinylidene olefin.The olefin has a sufficient number of carbon atoms such that theresulting copolymer is soluble in lubricating oil.

A. Unsaturated Acidic Reactant

The term "unsaturated acidic reactants" refers to maleic or fumaricreactants of the general formula: ##STR3## wherein X and X' are the sameor different, provided that at least one of X and X' is a group that iscapable of reacting to esterify alcohols, form amides or amine saltswith ammonia or amines, form metal salts with reactive metals orbasically reacting metal compounds and otherwise function to acylate.

Typically, X and X' are --OH, --O--hydrocarbyl, --OM⁺ where M⁺represents one equivalent of a metal, ammonium or amine cation, --NH₂,--Cl, --Br, and taken together X and X' can be --O-- so as to form ananhydride. Preferably, X and X' are such that both carboxylic functionscan enter into acylation reactions. Preferred are acidic reactants whereX and X' are each independently selected from the group consisting of--OH, --Cl, --O-- lower alkyl and when taken together, X and X' are--O--. Maleic anhydride is the preferred acidic reactant. Other suitableacidic reactants include electron-deficient olefins such as monophenylmaleic anhydride; monomethyl, dimethyl, monochloro, monobromo,monofluoro, dichloro and difluoro maleic anhydride; N-phenyl maleimideand other substituted maleimides; isomaleimides; fumaric acid, maleicacid, alkyl hydrogen maleates and fumarates, dialkyl fumarates andmaleates, fumaronilic acids and maleanic acids; and maleonitrile, andfumaronitrile.

B. High Molecular Weight olefin

The term "high molecular weight olefins" refers to olefins (includingpolymerized olefins having a residual unsaturation) of sufficientmolecular weight and chain length to lend solubility in lubricating oilto their reaction products. Typically olefins having about 32 carbons orgreater (preferably olefins having about 52 carbons or more) suffice.

The term "soluble in lubricating oil" refers to the ability of amaterial to dissolve in aliphatic and aromatic hydrocarbons such aslubricating oils or fuels in essentially all proportions.

High molecular weight olefins are generally mixtures of molecules havingdifferent molecular weights and can have at least one branch per 6carbon atoms along the chain, preferably at least one branch per 4carbon atoms along the chain, and particularly preferred that there beabout one branch per 2 carbon atoms along the chain. These branchedchain olefins may conveniently comprise polyalkenes prepared by thepolymerization of olefins of from 3 to 6 carbon atoms, and preferablyfrom olefins of from 3 to 4 carbon atoms, and more preferably frompropylene or isobutylene. The addition-polymerizable olefins employedare normally 1-olefins. The branch may be of from 1 to 4 carbon atoms,more usually of from 1 to 2 carbon atoms and preferably methyl.

Preferably, the high molecular weight olefin is a high molecular weightalkylvinylidene olefin, but it can also be an alpha olefin. Thepreferred alkylvinylidene isomer comprises a methyl- or ethylvinylideneisomer, more preferably the methylvinylidene isomer.

The term "alkylvinylidene" or "alkylvinylidene isomer" refers to highmolecular weight olefins and polyalkylene components having thefollowing vinylidene structure ##STR4## wherein R is alkyl orsubstituted alkyl of sufficient chain length to give the resultingmolecule solubility in lubricating oils and fuels, thus R generally hasat least about 30 carbon atoms, preferably at least about 50 carbonatoms and Rv is lower alkyl of about 1 to about 6 carbon atoms.

The term "alpha olefin" refers to high molecular weight olefins andpolyalkylene components having the following structure ##STR5## whereinR is alkyl or substituted alkyl of sufficient chain length to give theresulting molecule solubility in lubricating oils and fuels, thus Rgenerally has at least about 30 carbon atoms, preferably at least about50 carbon atoms.

As used herein, the term "succinic ratio" refers to the average numberof succinic groups per polyolefin group in the alkenyl or alkyl succinicanhydride reaction product of maleic anhydride and polyolefin. Forexample, a succinic ratio of 1.0 indicates an average of one succinicgroup per polyolefin group in the alkenyl or alkyl succinic anhydrideproduct. Likewise, a succinic ratio of 1.35 indicates an average of 1.35succinic groups per polyolefin group in the alkenyl or alkyl succinicarthydride product, and so forth.

The succinic ratio can be calculated from the saponification number (mgKOH per gram of sample), the actives content of the alkenyl or alkylsuccinic arthydride product and the molecular weight of the startingpolyolefin. The actives content of the alkenyl or alkyl succinicanhydride product is measured in terms of the actives fraction, whereinan actives fraction of 1.0 is equivalent to 100 weight percent actives.Accordingly, an actives fraction of 0.5 would correspond to 50 weightpercent actives.

The succinic ratio of the alkenyl or alkyl succinic anhydride product ofmaleic anhydride and polyolefin can be calculated in accordance with thefollowing equation: ##EQU1## wherein P=saponification number of thealkenyl or alkyl succinic anhydride sample (mg KOH/g)

A=actives fraction of the alkenyl or alkyl succinic anhydride sample

M_(po) =number average molecular weight of the starting polyolefin

M_(ma) =98 (molecular weight of maleic anhydride)

C=conversion factor=112220 (for conversion of gram-moles of alkenyl oralkyl succinic anhydride per gram of sample to milligrams of KOH pergram of sample)

The saponification number, P, can be measured using known procedures,such as the procedure described in ASTM D94.

The actives fraction of the alkenyl or alkyl succinic arthydride can bedetermined from the percent of unreacted polyolefin according to thefollowing procedure. A 5.0 gram sample of the reaction product of maleicanhydride and polyolefin is dissolved in hexane, placed in a column of80.0 grams of silica gel (Davisil 62, a 140 angstrom pore size silicagel), and eluted with 1 liter of hexane. The percent unreactedpolyolefin is determined by removing the hexane solvent under vacuumfrom the eluent and weighing the residue. Percent unreacted polyolefinis calculated according to the following formula: ##EQU2##

The weight percent actives for the alkenyl or alkyl succinic anhydrideproduct is calculated from the percent unreacted polyolefin using theformula: ##EQU3##

The actives fraction of the alkenyl or alkyl succinic anhydride is thencalculated as follows: ##EQU4##

The especially preferred high molecular weight olefins used to preparethe copolymers of the present invention are polyisobutenes whichcomprise at least about 20% of the more reactive methylvinylideneisomer, preferably at least 50% and more preferably at least 70%.Suitable polyisobutenes include those prepared using BF₃ catalysis. Thepreparation of such polyisobutenes in which the methylvinylidene isomercomprises a high percentage of the total composition is described inU.S. Pat. Nos. 4,152,499 and 4,605,808.

Preferred are polyisobutenes having average molecular weights of about500 to about 5000. Especially preferred are those having averagemolecular weights of about 900 to about 2500.

C. Copolymer

The copolymers of the present invention are prepared by reacting a highmolecular weight olefin and an unsaturated acidic reactant in thepresence of a free radical initiator. Preferably, at least about 20% ofthe total olefin composition comprises the alkylvinylidene isomer.

The copolymers of the present invention differ from the copolymersdisclosed in U.S. Pat. No. 5,112,507 in that the ratio of anhydridegroups to the hydrocarbon groups in the present invention is at least1.3. Preferably, the ratio is between 1.3 and 2.0.

Copolymers of an olefin, including high molecular weight olefins with anunsaturated acidic reactant are well known in the art (U.S. Pat. Nos.3,461,108; 3,560,455; 3,560,456; 3,560,457; 3,580,893; 3,706,704;3,729,450; 3,729,451; and 5,112,507). As reported by Trivedi andCulbertson in "Maleic Anhydride: 1982," Plenum Press, pg. 288, as arule, olefin-maleic anhydride copolymerizations, run in the presence offree radical initiators, give only equimolar copolymers. Moreover,conditions are known where random copolymers may be prepared thatcontain less than equimolar amounts of maleic anhydride. However,copolymers that contain greater than 1.3 anhydride groups perhydrocarbon group are less well known. Surprisingly, during the courseof our studies we have now found how to produce these desirablematerials.

What is required is to use an unsaturated acidic reagent to polyolefincharge mole ratio (CMR) of greater than 1.3:1 and a sufficienttemperature of reaction to produce a ratio of anhydride groups tohydrocarbon group of at least 1.3:1. The greater the CMR the greater thelikelihood of producing a product with greater than 1.3 anhydride groupsper hydrocarbon chain. In addition the temperature of the reaction of anunsaturated acidic reagent with an olefin is an important factor. Forexample, at a CMR of 2.0, a higher ratio of anhydride groups tohydrocarbon chain is obtained at 160° C. than at 130° C. The CMR andtemperature of the reaction can vary over a wide range such that thecombination of CMR and temperature is sufficient to produce the desiredresult.

Since the high molecular weight olefins used to prepare the copolymersof the present invention are generally mixtures of individual moleculesof different molecular weights, individual copolymer molecules resultingwill generally contain a mixture of high molecular weight polyalkylgroups of varying molecular weight.

The copolymers of the present invention have the general formula:##STR6## wherein W' and Z' are independently selected from the groupconsisting of --OH, --O-- lower alkyl or taken together are --O-- toform a succinic anhydride group, n is one or greater, and R₁, R₂, R₃ andR₄ are selected from hydrogen, lower alkyl of about 1 to 6 carbon atomsand higher molecular weight polyalkyl wherein x and y are 1 or greater,such that the sum of x is at least 1.3 times the sum of y for the totalmixture. Either R₁ and R₂ are hydrogen and one of R₃ and R₄ is loweralkyl or hydrogen and the other is high molecular weight polyalkyl, orR₃ and R₄ are hydrogen and one of R₁ and R₂ is lower alkyl or hydrogenand the other is high molecular weight polyalkyl. The variables x and ycan vary over the length of the polymer.

The term "high molecular weight polyalkyl" refers to polyalkyl groups ofsufficient molecular weight and hydrocarbyl chain length that theproducts prepared having such groups are soluble in lubricating oil.Typically these high molecular weight polyalkyl groups have at leastabout 30 carbon atoms, preferably at least about 50 carbon atoms. Thesehigh molecular weight polyalkyl groups may be derived from highmolecular weight olefins.

In a preferred embodiment, when maleic anhydride is used as theunsaturated acidic reactant, the reaction produces copolymerspredominately of the following formula: ##STR7## wherein n is about 1 toabout 100, preferably about 2 to about 20, more preferably 2 to 10, andR₁, R₂, R₃ and R₄ are selected from hydrogen, lower alkyl of about 1 to6 carbon atoms and higher molecular weight polyalkyl wherein x and y are1 or greater, such that the sum of x is at least 1.3 times the sum of yfor the total mixture. Either R₁ and R₂ are hydrogen and one of R₃ andR₄ is lower alkyl and the other is high molecular weight polyalkyl, orR₃ and R₄ are hydrogen and one of R₁ and R₂ is lower alkyl and the otheris high molecular weight polyalkyl. The variables x and y can vary overthe length of the polymer.

Preferably, the high molecular weight polyalkyl group has at least about30 carbon atoms (more preferably at least about 50 carbon atoms).Preferred high molecular weight polyalkyl groups include polyisobutylgroups. Preferred polyisobutyl groups include those having averagemolecular weights of about 500 to about 5000, more preferably from about900 to about 2500. Preferred lower alkyl groups include methyl andethyl; especially preferred lower alkyl groups include methyl.

Generally, such copolymers contain an initiator group, I, and aterminator group, T, as a result of the reaction with the free radicalinitiator used in the polymerization reaction. In such a case, theinitiator and terminator groups may be ##STR8## where R₇ is hydrogen,alkyl, aryl, alkaryl, cycloalkyl, alkoxy, cycloalkoxy, acyl, alkenyl,cycloalkenyl, alkynyl; or alkyl, aryl or alkaryl optionally substitutedwith 1 to 4 substituents independently selected from nitrile, keto,halogen, nitro, alkyl, aryl, and the like. Alternatively, the initiatorgroup and/or terminator group may be derived from the reaction productof the initiator with another material such as solvent; for example, theinitiator may react with toluene to produce a benzyl radical.

The copolymers of the present invention differ from the PIBSAs preparedby the thermal process in that the thermal process products contain adouble bond and a singly substituted succinic anhydride group. Thecopolymers of the present invention differ from the PIBSAs prepared bythe chlorination process, since those products contain a double bond, aring, other than a succinic anhydride ring or one or more chlorineatoms. The copolymers of the present invention differ from thecopolymers of unsaturated acidic reactants and high molecular weightolefins in that ratio of anhydride groups to hydrocarbon groups is atleast 1.3:1.

As noted above, the copolymers of the present invention are prepared byreacting a reactive high molecular weight olefin and an unsaturatedacidic reactant in the presence of a free radical initiator. Thereaction may be conducted at a temperature of about -30° C. to about210° C., preferably from about 120° C. to about 180° C.

The reaction may be conducted neat, that is, both the high molecularweight olefin, and acidic reactant and the free radical initiator arecombined in the proper ratio, and then stirred at the reactiontemperature.

Alternatively, the reaction may be conducted in a diluent. For example,the reactants may be combined in a solvent. Suitable solvents includethose in which the reactants and free radical initiator are soluble andinclude acetone, tetrahydrofuran, chloroform, methylene chloride,dichloroethane, toluene, dioxane, chlorobenzene, xylenes, or the like.After the reaction is complete, volatile components may be stripped off.When a diluent is employed, it is preferably inert to the reactants andproducts formed and is generally used in an amount sufficient to ensureefficient stirring.

The reaction solvent, as noted above, must be one that dissolves boththe acidic reactant and the high molecular weight olefin. It isnecessary to dissolve the acidic reactant and high molecular weightolefin so as to bring them into intimate contact in the solutionpolymerization reaction. It has been found that the solvent must also beone in which the resultant copolymers are soluble.

Suitable solvents include liquid saturated or aromatic hydrocarbonshaving from six to 20 carbon atoms; ketones having from three to fivecarbon atoms; and liquid saturated aliphatic dihalogenated hydrocarbonshaving from one to five carbon atoms per molecule, preferably from oneto three carbon atoms per molecule. By "liquid" is meant liquid underthe conditions of polymerization. In the dihalogenated hydrocarbons, thehalogens are preferably on adjacent carbon atoms. By "halogen" is meantF, Cl and Br. The amount of solvent must be such that it can dissolvethe acidic reactant and high molecular weight olefin in addition to theresulting copolymers. The volume ratio of solvent to high molecularweight olefin is suitably between 1:1 and 100:1 and is preferablybetween 1.5:1 and 4:1.

Suitable solvents include the ketones having from three to six carbonatoms and the saturated dichlorinated hydrocarbons having from one tofive, more preferably one to three, carbon atoms.

Examples of suitable solvents include, but are not limited to:

1. ketones, such as: acetone; methylethylketone; diethylketone; andmethylisobutylketone;

2. aromatic hydrocarbons, such as: benzene; xylene; and toluene;

3. saturated dihalogenated hydrocarbons, such as: dichloromethane;dibromomethane; 1-bromo-2-chloroethane; 1,1-dibromoethane;1,1-dichloroethane; 1,2-dichloroethane; 1,3-dibromopropane;1,2-dibromopropane; 1,2-dibromo-2-methylpropane; 1,2-dichloropropane;1,1-dichloropropane; 1,3-dichloropropane; 1-bromo-2-chloropropane;1,2-dichlorobutane; 1,5-dibromopentane; and 1,5-dichloropentane; or

4. mixtures of the above, such as: benzenemethylethylketone.

The reaction can also be carried out using a process similar to the onedescribed by U.S. Pat. No. 5,175,225 where the oligomeric copolymer,which is the reaction product of the unsaturated acidic reactant and thehigh molecular weight olefin, is used as a "solvent" for the unsaturatedacidic reactant, free radical initiator, and the high molecular weightolefin. In this process, the unsaturated acidic reactant, free radicalinitiator, and high molecular weight olefin are added to a sufficientamount of oligomeric copolymer to afford solubility of the reactants.

In addition copolymerization can be accomplished in the presence ofdispersing agents. This copolymerization is called suspensioncopolymerization.

A charge mole ratio (CMR) greater than 1.3 is required to produce thecopolymers of this invention. The CMR is defined as the ratio of thenumber of moles of maleic anhydride to the number of moles ofpolybutene.

In addition the temperature of reaction must be sufficient to facilitatethe production of copolymer with a succinic ratio greater than 1.3.Generally, temperatures in excess of about 110° C. are required.However, the temperature required to produce a copolymer with a succinicratio greater than 1.3 is also dependent on the CMR and theconcentration. In general, the higher the CMR and the more concentratedthe reaction mixture, the lower the temperature of reaction that isrequired to produce a copolymer with greater than a 1.3 succinic ratio.

In general, the copolymerization can be initiated by any free radicalinitiator. Such initiators are well known in the art. However, thechoice of free radical initiator may be influenced by the reactiontemperature employed.

The preferred free-radical initiators are the peroxide-typepolymerization initiators and the azo-type polymerization initiators.Radiation can also be used to initiate the reaction, if desired.

The peroxide-type free-radical initiator can be organic or inorganic,the organic having the general formula: R₃ OOR₃ ' where R₃ is anyorganic radical and R₃ ' is selected from the group consisting ofhydrogen and any organic radical. Both R₃ and R₃ ' can be organicradicals, preferably hydrocarbon, aroyl, and acyl radicals, carrying, ifdesired, substituents such as halogens, etc. Preferred peroxides includedi-tert-butyl peroxide, tert-butyl peroxybenzoate, and dicumyl peroxide.

Examples of other suitable peroxides, which in no way are limiting,include benzoyl peroxide; lauroyl peroxide; other tertiary butylperoxides; 2,4-dichlorobenzoyl peroxide; tertiary butyl hydroperoxide;cumene hydroperoxide; diacetyl peroxide; acetyl hydroperoxide;diethylperoxycarbonate; tertiary butyl perbenzoate; and the like.

The azo-type compounds, typified by alpha,alpha'-azobisisobutyronitrile,are also well-known free-radical promoting materials. These azocompounds can be defined as those having present in the molecule group--N═N wherein the balances are satisfied by organic radicals, at leastone of which is preferably attached to a tertiary carbon. Other suitableazo compounds include, but are not limited to, p-bromobenzenediazoniumfluoborate; p-tolyldiazoaminobenzene; p-bromobenzenediazonium hydroxide;azomethane and phenyldiazonium halides. A suitable list of azo-typecompounds can be found in U.S. Pat. No. 2,551,813, issued May 8, 1951 toPaul Pinkney.

The amount of initiator to employ, exclusive of radiation, of course,depends to a large extent on the particular initiator chosen, the highmolecular olefin used and the reaction conditions. The initiator must,of course, be soluble in the reaction medium. The usual concentrationsof initiator are between 0.001:1 and 0.2:1 moles of initiator per moleof acidic reactant, with preferred amounts between 0.005:1 and 0.10:1.

The polymerization temperature must be sufficiently high to decomposethe initiator to produce the desired free-radicals. A suitable initiatoris ditertiarybutyl peroxide, which decomposes at a sufficient rate overthe temperature range of 120° to 180° C.

The reaction pressure should be sufficient to maintain the solvent andthe free radical initiator in the liquid phase. Pressures can thereforevary between about atmospheric and 100 psig or higher

The reaction time is usually sufficient to result in the substantiallycomplete conversion of the acidic reactant and high molecular weightolefin to copolymer. The reaction time is suitable between one and 24hours, with preferred reaction times between two and ten hours.

The copolymer is conveniently separated from solvent and unreactedacidic reactant by conventional procedures such as phase separation,solvent distillation, precipitation and the like. If desired, dispersingagents and/or cosolvents may be used during the reaction.

The isolated copolymer may then be reacted with a polyamine to form apolymeric succinimide. The preparation and characterization of suchpolysuccinimides and their treatment with other agents to give otherdispersant compositions is described herein.

Preferred copolymers include those prepared using a polyisobutene ofaverage molecular weight of about 500 to about 5000, preferably of about950 to about 2500 and wherein at least about 50 percent of the totalpolyisobutene comprises the alkylvinylidene isomer. Preferredalkylvinylidene isomers include methylvinylidene and ethylvinylidene.Especially preferred is methylvinylidene. Particularly preferredcopolymers have an average molecular weight of about 900 to about 2500.

D. Polysuccinimides

The copolymer of the present invention can be reacted with a polyaminehaving at least one basic nitrogen atom to form polyaminopolysuccinimides. Polysuccinimides that may be prepared includemonopolysuccinimides, bis-polysuccinimides, higher succinimides, ormixtures thereof. The polysuccinimides produced may depend on the chargemole ratio of polyamine to succinic groups in the copolymer molecule andthe particular polyamine used. Charge mole ratios of polyamine tosuccinic group in copolymer of about 1:1 may produce predominatelymonopolysuccinimide. Charge mole ratios of polyamine to succinic groupin copolymer of about 1:2 may produce predominately bis-polysuccinimide.Higher polysuccinimides may be produced if there is branching in thepolyamine so that it may react with a succinic group from each ofgreater than two copolymer molecules. Preferably, the charge mole ratioof polyamine to succinic groups in copolymer is from about 1:1 to about0.1:1.

The preparation of polyamino polysuccinimides by reacting copolymerswith a polyamine is fully described in U.S. Pat. No. 5,112,507, which ishereby incorporated by reference for all purposes. Reference is made toU.S. Pat. No. 5,112,507 for a full description of preparation proceduresfor producing polysuccinimides.

The polyamine employed to prepare the polyamino polysuccinimides ispreferably polyamine having from 2 to about 12 amine nitrogen atoms andfrom 2 to about 40 carbon atoms. The polyamine is so selected so as toprovide at least one basic amine per succinimide group. The polyaminepreferably has a carbon-to-nitrogen ratio of from about 1:1 to about10:1.

The more preferred polyamines employed in this reaction are generallyrepresented by the formula:

    H.sub.2 N(YNH).sub.a H

wherein Y is an alkylene group of 2 to 10 carbon atoms, preferably from2 to 6 carbon atoms, and a is an integer from about 1 to 11, preferablyfrom 1 to 6. However, the preparation of these alkylene polyamines doesnot produce a single compound and cyclic heterocycles, such aspiperazine, may be included to some extent in the alkylene diamines.Reference is made to U.S. Pat. No. 5,112,507 for a full description ofpreferred polyamines.

Preferred monopolysuccinimides include those having the followingformula: ##STR9## wherein Am is a linking group having from 0 to 10amine nitrogen atoms and from 2 to 40 carbon atoms; n is 1 or greater;R₅ and R₆ are independently hydrogen, lower alkyl of 1 to 6 carbonatoms, phenyl or taken together are alkylene of 3 to 6 carbon atoms togive a ring; and wherein x and y are 1 or greater, such that the sum ofx is at least 1.3 times the sum of y for the total mixture. R₁, R₂, R₃,and R₄ are selected so that either R₁ and R₂ are hydrogen and one of R₃and R₄ is lower alkyl and the other is high molecular weight polyalkyl,or R₃ and R₄ are hydrogen and one of R₁ and R₂ is lower alkyl and theother is high molecular weight polyalkyl.

Preferred polysuccinimides include those which partially comprise atleast in part a bis-polysuccinimide structure. Some of these preferredpolysuccinimides are random polysuccinimides that comprise unitsselected from: ##STR10## wherein Am is a linking group having from about0 to 10 amine nitrogen atoms and from about 2 to 40 carbon atoms; R₁,R₂, R₃, R₄, R₁ ', R₂ ', R₃ ', R₄ ', R₁ ", R₂ ", R", and R₄ " areselected from hydrogen, lower alkyl of one to 6 carbon atoms and highmolecular weight polyalkyl, wherein x, y, and y' are 1 or greater, suchthat the sum of x is at least 1.3 times the combined sum of y and y' forthe total mixture; and a, a', b and b' are sites for a covalent bond;provided that at least one a or a' site of each unit is covalentlybonded to a b or b' site. Either R₁ and R₂ are hydrogen and one of R₃and R₄ is lower alkyl and the other is polyalkyl, or R₃ and R₄ arehydrogen and one of R₁ and R₂ is lower alkyl and the other is polyalkyl;either R₁ and R₂ ' are hydrogen and one of R₃ ' and R₄ ' is lower alkyland the other is polyalkyl, or R₃ ' and R₄ ' are hydrogen and one of R₁' and R₂ ' is lower alkyl and the other is polyalkyl; and either R₁ "and R₂ " are hydrogen and one of R₃ " and R₄ " is lower alkyl and theother is polyalkyl or R₃ " and R₄ " are hydrogen and one of R₁ " and R₂" is lower alkyl and the other is polyalkyl and R₅ and R₆ areindependently hydrogen, lower alkyl of 1 to 6 carbon atoms, phenyl ortaken together are alkylene of 3 to 6 carbon atoms to give a ring.

Preferred high molecular weight polyalkyl groups include polyisobutylgroups having at least about 30 carbon atoms, more preferably, at leastabout 50 carbon atoms. Especially preferred are polyisobutyl groupshaving an average molecular weight of about 500 to about 5000, morepreferably from about 900 to about 2500.

Preferred lower alkyl groups include methyl and ethyl. Especiallypreferred are compounds where the lower alkyl group is methyl.

Preferred are compounds where R₅ and R₆ are hydrogen or methyl.Especially preferred R₅ and R₆ groups include hydrogen.

Preferred are Am groups having from about 0 to about 10 amine nitrogenatoms and from about 2 to about 40 carbon atoms. More preferred are Amgroups of the formula --[(ZNH)_(p) Z']-- wherein Z and Z' areindependently alkylene of from about 2 to about 6 carbon atoms and p isan integer from 1 to 6. Especially preferred are Am groups where Z andZ' are ethylene and p is 2, 3 or 4.

Preferred are random polysuccinimides where the average sum of A and Bunits is from about 2 to about 50. Preferred are random polysuccinimideshaving molecular weights of from about 10,000 to about 150,000.Preferred are compounds in which the bis-succinimide structurepredominates, that is, those having more B units than A units,preferably on the order of about 2 to about 10 times as many B units asA units. Such compounds are preferred in part due to their high averagemolecular weights, on the order of about 10,000 to about 150,000, whichmay be related to their exhibiting an advantageous V.I. credit as wellas dispersantability when used in a lubricating oil composition.

Higher polysuccinimides are prepared by reacting the copolymers of thepresent invention with a polyamine having branching such that it canreact with a succinic group from each of greater than two copolymermolecules. Due to this crosslinking, it is believed that these higherpolysuccinimides may have gel-like properties besides the dispersantproperties possessed by the other polysuccinimides.

A polysuccinimide having at least one primary or secondary amine groupcan be reacted with a cyclic carbonate or it can be reacted with a boroncompound, such as boron oxide, boron halide, boric acid or esters ofboric acid. Reference is made to U.S. Pat. No. 5,112,507 for a fulldescription of those post treatments.

The copolymers, polysuccinimides and modified polysuccinimides of thisinvention are useful as detergent and dispersant additives when employedin lubricating oils and lubricating oil concentrates. The lubricatingoil composition has an oil of lubricating viscosity and a dispersanteffective amount of the copolymers, polysuccinimides or modifiedpolysuccinimides. The lubricating oil concentrate has from 90 to 50weight percent of an oil of lubricating viscosity and from 10 to 50weight percent of copolymers, polysuccinimides or modifiedpolysuccinimides. Other additives which may be present in theformulation include rust inhibitors, foam inhibitors, corrosioninhibitors, metal deactivators, pour point depressants, antioxidants,V.I. improvers (either dispersant or nondispersant), and a variety ofother well-known additives. It is also contemplated the additives ofthis invention may be employed as dispersants and detergents inhydraulic fluids, marine crankcase lubricants and the like.

Also, the copolymers, polysuccinimides and modified polysuccinimides ofthis invention are useful in fuel compositions and fuel concentrates.The fuel composition has a hydrocarbon boiling in a gasoline or dieselrange and from 30 to 5000 parts per million of copolymers,polysuccinimides or modified polysuccinimides. The fuel concentrate hasan inert stable oleophilic organic solvent boiling in the range of 150°F. to 400° F. and from 5 to 50 weight percent copolymers,polysuccinimides or modified polysuccinimides.

EXAMPLES

The invention will be further illustrated by following examples, whichset forth particularly advantageous method embodiments. While theExamples are provided to illustrate the present invention, they are notintended to limit it.

EXAMPLE 1 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight and a CMR of 2.0

To a 22 L, 3 neck flask equipped with a stirrer, condenser and heatingmantle was added 12068 g (9.28 mol) polybutene of 1300 molecular weight,and about 70% methylvinylidene content (Glissopal EC 3251). This washeated to 110° C. To this was added maleic anhydride (1820 g, 18.57mol). The maleic anhydride/polybutene charge mole ratio was 2.0. Themixture was heated to 160° C. and di-t-butylperoxide (67.74 g, 0.464mol) was added dropwise over a five hour period. Then an additionalamount of di-t-butylperoxide (33.87 g, 0.232 mol) was added dropwiseover five hours and the reaction was heated an additional 5 hours at160° C. The di-t-butylperoxide/polybutene charge mole ratio was 0.075.The reaction was then heated to 200° C. and excess maleic anhydrideremoved in a vacuum. To this product was then added 100N diluent oil(2310 g). The material was filtered to give a product with a SAP numberof 56.6 mg KOH/g sample. (SAP number was determined by using ASTMprocedure D94-80.) The succinic ratio was calculated to be 1.5. Thisproduct contained 50% active material.

EXAMPLE 2 Preparation of a copolymer from maleic anhydride andpolybutene with 2400 molecular weight and a CMR of 2.0

The procedure in Example one was repeated except that instead of usingpolybutene of 1300 molecular weight, 8310 g (3.46 mol) polybutene of2400 molecular weight, (Glissopal EC 3252), was used. In this examplethe maleic anhydride/polybutene charge mole ratio was 2.0 and thedi-t-butylperoxide/polybutene charge mole ratio was 0.05. Half of themaleic anhydride (169.54 g, 1.73 mol) and one quarter of thedi-t-butylperoxide (6.32 g, 0.043 mol) was added initially. The rest ofthe maleic anhydride and di-t-butylperoxide was added after 5 hours ofheating. After the completion of the reaction the excess maleicanhydride was removed at 200° C. in a vacuum, 3780 g diluent oil wasadded and the product was filtered. This product had a SAP number of26.4 mg KOH/g sample and contained 40% actives. The succinic ratio wascalculated to be 1.5.

Example 1 and 2 show that a copolymer with a succinic ratio of 1.5 isproduced in good yield over a range of polybutene molecular weights(1300 to 2400) at 160° C. reaction temperature and a CMR of 2.0.

EXAMPLE 3 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight using a CMR of 1.0

To a 500 ml 3-neck flask fitted with a thermometer, condenser,mechanical stirrer, and heating mantle was added 130 g Ultravis 30 (0.1mol), 100 g 1,1,2,2-tetrachloroethane, and 9.8 g maleic anhydride (0.1mol). The Ultravis 30 contained about 65% methylvinylidene content. Thiswas heated to 100° C. and after one hour di-t-butylperoxide (1.46 g,0.01 mol) was added and the temperature rose to 140° C. This was heatedovernight. Then the 1,1,2,2-tetrachloroethane was removed in a vacuum.The residue was dissolved in hexane and filtered to remove unreactedmaleic anhydride. The hexane was removed in a vacuum. The product had aSAP number of 45.0 and contained 59.3% actives. The succinic ratio wascalculated to be 1.0.

Example 3 shows that when a CMR of 1.0 was used and a temperature of140° C. was used a copolymer with a succinic ratio greater than 1.3 wasnot produced.

EXAMPLE 4 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight using a CMR of 0.33

The procedure of Example 3 was repeated exactly except that 0.15 molpolybutene and 0.05 mol maleic anhydride was used. This product had aSAP number of 15.0 mg KOH/g sample and contained 31.7% actives. Thesuccinic ratio was calculated to be 0.6.

Example 4 shows that when a CMR of 0.33 was used at a temperature of140° C. a copolymer with a succinic ratio greater than 1.3 was notproduced.

EXAMPLE 5 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight using a CMR of 3.0

The procedure of Example 3 was repeated exactly except that 0.05 molpolybutene and 0.15 mol maleic anhydride was used. This product had aSAP number of 78.1 mg KOH/g sample and contained 67% actives. Thesuccinic ratio was calculated to be 1.5.

Example 5 shows that when a CMR of 3.0 was used at a temperature of 140°C. a copolymer with a succinic ratio of 1.5 was produced.

EXAMPLE 6 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight with a CMR of 3.0 using adi-t-amyl peroxide.

The procedure of Example 5 was repeated exactly except thatdi-t-amylperoxide (1.74 g, 0.01 mol) was used instead ofdi-t-butylperoxide. The product from this reaction had a SAP number of82.1 mg KOH/g sample and contained 65% actives. The succinic ratio wascalculated to be 1.6.

Example 6 shows that other initiators besides di-t-butylperoxide can beused.

EXAMPLE 7 Preparation of a copolymer from maleic anhydride andpolybutene with 1300 molecular weight with a CMR of 3.0 usingt-butylperoctoate at 84° C.

To a 500 ml 3-necked flask equipped with a mechanical stirrer,condenser, thermometer, and heating mantle was added 65 g (0.05 mol)Ultravis 30 (containing about 65% methylvinylidene content), 14.7 g(0.15 mol) maleic anhydride, and 100 g 1,2-dichloroethane. This washeated to 60° C. and to this was added 2.19 g (0.01 mol)t-butylperoctoate. The mixture was heated to 84° C. and heatedovernight. Then the solvent was removed in a vacuum. The product wasdissolved in hexane and filtered to remove unreacted maleic anhydride.The hexane was removed in a vacuum. The product had a SAP number of 54.6mg KOH/g sample, and contained 65% actives. The succinic ratio wascalculated to be only 1.1.

Example 7 shows that when the temperature of reaction is 84° C. using aCMR of 3.0, a copolymer with a succinic ratio greater than 1.3 was notproduced.

EXAMPLE 8 Preparation of a copolymer from maleic anhydride andpolybutene with 2400 molecular weight with a CMR of 2.0 in 100 neutraloil as diluent at 130° C.

To a 2 L 3-neck flask equipped with a thermometer, mechanical stirrer,and heating mantle was added 480 g (0.2 mol) Glissopal ES 3252 (2400molecular weight and 70% methylvinylidene content), 39.2 g (0.4 mol)maleic anhydride, and 100 g 100 neutral diluent oil (Chevron 100NR).This was heated to 80° C. and to this was added 2.92 g (0.02 mol)di-t-butylperoxide. The temperature was increased to 130° C. and heatedovernight. Then the excess maleic anhydride was removed in a vacuum. Theproduct was dissolved in hexane and filtered. The hexane was removed ina vacuum. A product was obtained that had a SAP number of 27.8 mg KOH/gsample and contained 50% actives. The succinic ratio was calculated tobe 1.2.

Example 8 shows that 100 neutral oil is a satisfactory diluent oil forthe reaction. The succinic ratio was less than 1.3, however, due to acombination of low CMR (2.0) and temperature (130° C.).

EXAMPLE 9 Preparation of a copolymer from maleic anhydride andpolybutene with 2400 molecular weight with a CMR of 2.0 in 100 neutraloil as diluent at 160° C.

The procedure of Example 8 was repeated exactly except that 160° C. wasused. This product had a SAP number of 40.9 mg KOH/g sample andcontained 53.2% actives. The succinic ratio was calculated to be 1.8.

This experiment shows that in order to get a copolymer with a succinicratio greater than 1.3 using a CMR of 2.0 and 100 neutral oil asdiluent, a temperature of about 160° C. was needed.

EXAMPLE 10 Preparation of a polysuccinimide using the copolymer fromExample 1, and DETA as the polyamine

To a 1 L 3-neck flask equipped with a mechanical stirrer, thermometer,Dean Stark trap, condenser and a heating mantle was added 300.69 g(0.1517 mol of succinic groups) of the copolymer of Example 1. This washeated to 140° C. and to this was added 13.61 g DETA (0.1319 mol). TheDETA/copolymer CMR was 0.87. This was heated to 160° C. for about 7hours collecting the water in the Dean Stark trap as the reactionproceeded. The polysuccinimide product was analyzed and found to contain1.63%N, a TBN of 23.7, and a viscosity at 100° C. of 2696 cSt. Thesuccinic ratio was 1.5.

EXAMPLES 11-17 Preparation of polysuccinimides using different CMRs anddifferent polyamines

The procedure of Example 10 was followed exactly except that differentpolyamine/copolymer CMRs and different polyamines were used. Theproducts produced are reported in Table 1. The succinic ratio was 1.5.

EXAMPLE 18 Preparation of a post treated polysuccinimide using a cycliccarbonate

To a 1 L 3-neck flask equipped with a mechanical stirrer, condenser,Dean Stark trap, and mechanical stirrer was added 311.3 g of the bisDETA PIBSA 1300 polysuccinimide from Example 14. This was heated to 160°C. and to this was added 23.5 g ethylene carbonate (0.267 mol). This washeated at 160° C. overnight. The post treated polysuccinimide wasanalyzed and found to contain 1.02% N, a TBN of 8.9, and a viscosity at100C of 2687 cSt.

EXAMPLE 19 Preparation of post treated polysuccinimide using TETA as thepolyamine

The procedure of Example 18 was repeated except that 313.5 g of the bisTETA PIBSA 1300 polysuccinimide from Example 15 was used. This wasreacted with 30.0 g (0.34 mol) ethylene carbonate. The properties ofthis product are reported in Table 1.

EXAMPLE 20 Preparation of post treated polysuccinimide using TEPA as thepolyamine

The procedure of Example 18 was repeated except that 316.2 g of the bisTEPA PIBSA 1300 polysuccinimide from Example 16 was used. This wasreacted with 38.6 g (0.439 mol) ethylene carbonate. The properties ofthis product are reported in Table 1.

EXAMPLE 21 Preparation of post treated polysuccinimide using HPA as thepolyamine

The procedure of Example 18 was repeated except that 326.8 g of the bisHPA PIBSA 1300 polysuccinimide from Example 17 was used. This wasreacted with 62.8 g (0.714 mol) ethylene carbonate. The properties ofthis product are reported in Table 1.

EXAMPLE 22 Preparation of a polysuccinimide using the copolymer fromExample 2 and DETA as the polyamine

To a 500 ml 3-neck flask equipped with a mechanical stirrer, Dean Starktrap, condenser, thermometer, and heating mantle was added 200.0 g ofthe copolymer from Example 2 (0.047 mol of succinic groups). Thereaction was heated to 110° C. and to this was added DETA (4.22 g, 0.041mol). The DETA/copolymer CMR was 0.87. The reaction was heated to 160°C. for 5 hours. The product was analyzed and found to contain 0.77% N,TBN of 16.07, a TAN of 1.34, and a viscosity at 100° C. of 1317 cSt. Thesuccinic ratio was 1.5

EXAMPLE 23-29 Preparation of polysuccinimides using different CMRs anddifferent polyamines

The procedure of Example 22 was repeated except that differentpolyamines and different polyamine/copolymer CMRs were used. Theanalytical data for these compounds are reported in Table 1. Thesuccinic ratio was 1.5.

EXAMPLE 30 Preparation of post treated polysuccinimide using a cycliccarbonate

To a 500 ml 3-neck flask equipped with a mechanical stirrer,thermometer, condenser and heating mantle was added 200 g of the bisDETA polysuccinimide from Example 26. This was heated to 165° C. and tothis was added ethylene carbonate 4.27 g (0.0486 mol). The ethylenecarbonate/basic nitrogen CMR for this reaction was 2.0. This was heatedat 165° C. for 5 hours. The product was analyzed and found to contain0.49% N, TBN of 4.87, a TAN of 0.22 and a viscosity at 100° C. of 1350cSt.

EXAMPLE 31-33 Preparation of other post treated polysuccinimides using acyclic carbonate

The procedure of Example 30 was followed except that differentpolysuccinimides were used. These all used an ethylene carbonate/basicnitrogen CMR of 2.0. These products were analyzed and the data isreported in Table 1.

COMPARATIVE EXAMPLES EXAMPLE A Preparation of a polysuccinimide from acopolymer that contains a succinic ratio of less than about 1.3 and apolybutene molecular weight of 1300

The procedure of Example 10 was followed except that a copolymer with asuccinic ratio of less than 1.3 was used. DETA was used as thepolyamine. The product was analyzed and found to contain 0.74% N, and aviscosity @100° C. of 1193 cSt.

EXAMPLE B-D Preparation of polysuccinimides from a copolymer thatcontains a succinic ratio of less than about 1.3 with differentpolyamines

The procedure of Example A was followed using TETA, TEPA, and HPA. Theseproducts were analyzed and the data is reported in Table 1.

EXAMPLE E Preparation of a polysuccinimide from a copolymer thatcontains a succinic ratio of less than about 1.3 and a polybutenemolecular weight of 2400

The procedure of Example 22 was followed except that a copolymer with asuccinic ratio of less than 1.3 was used. DETA was used as thepolyamine. The product was analyzed and found to contain 0.31% N, had aTBN of 3.3, and had a viscosity @100° C. of 571 cSt.

EXAMPLES F-H Preparation of polysuccinimides from a copolymer thatcontains a succinic ratio of less than about 1.3 with differentpolyamines

The procedure of Example D was followed except that TETA, TEPA and HPAwere used instead of DETA. These products were analyzed and the data isreported in Table 1.

Examples A through H had a succinic ratio of 1.0.

                  TABLE I                                                         ______________________________________                                                         POST                                                         EXAMPLE  CMR     TREAT    AMINE  % N  VIS   TBN                               ______________________________________                                        10       0.87             DETA   1.63 2696  23.7                              11       0.87             TETA   1.99 3321  37.4                              12       0.87             TEPA   2.65 4824  65.7                              13       0.87             HPA    3.53 14290 97.7                              14       0.5              DETA   1.00 2409  13.0                              15       0.5              TETA   1.27 3267  19.6                              16       0.5              TEPA   1.62 4049  33.4                              17       0.5              HPA    2.14 5523  49.8                              18       0.5     EC       DETA   1.02 2689  8.9                               19       0.5     EC       TETA   1.20 4187  12.9                              20       0.5     EC       TEPA   1.55 9249  15.7                              21       0.5     EC       HPA    2.02 90130 22.4                              22       0.87             DETA   0.77 1317  16.1                              23       0.87             TETA   1.01 1309  22.9                              24       0.87             TEPA   1.23 1599  35.0                              25       0.87             HPA    1.71 1856  37.0                              26       0.5              DETA   0.51 1338  5.8                               27       0.5              TETA   0.61 1491  10.6                              28       0.5              TEPA   0.76 1794  16.1                              29       0.5              HPA    1.04 2164  25.1                              30       0.5     EC       DETA   0.49 1350  4.9                               311      0.5     EC       TETA   0.73 1636  7.3                               32       0.5     EC       TEPA   0.82 2191  8.3                               33       0.5     EC       HPA    0.97 3703  11.7                              A        0.5              DETA   0.74 1193                                    B        0.5              TETA   0.91 971   15.4                              C        0.5              TEPA   1.08 1179  16.5                              D        0.5              HPA    1.46 1707  32.0                              E        0.5              DETA   0.31 571   3.3                               F        0.5              TETA   0.40 578   5.6                               G        0.5              TEPA   0.55 612   8.9                               H        0.5              HPA    0.68 672   18.2                              ______________________________________                                    

Some lubricating oil additives have been identified as being deleteriousto fluoroelastomers such as Viton that are currently used as gasketmaterials in automobile engines. European engine builders have nowplaced fluoroelastomer seal tests into their engine oil specifications.One such test is the Volkswagen VW3334 (September 1987) Seal Swell Test.This procedure is described in the Third Symposium of the EuropeanCoordination Council (CEC) 1989 in an article entitled "Engine and BenchAging Effects on the Compatibility of Fluoroelastomers with Engine Oils"by Dr. S. W. Harris and J. C. Downey of Amoco Petroleum AdditivesCompany.

The VW3334 (September 1987) Seal Swell Test was carried out on samplesof Viton from the Parker Prudifa Company, which were cut into dumbbellshapes, using a formulated lubricating test oil that containedsuccinimide dispersant, overbased detergent, antioxidant and viscosityindex improver materials at a bath temperature of 150° C. for a 96 hourimmersion time. The immersion procedure was similar to ASTM D471-79Standard Test Method for Rubber Property-Effect of Liquids. The Vitonsamples were then subjected to analysis of their tensile propertiesusing procedures similar to ASTM D412-87 Standard Test Method for RubberProperties in Tension. The properties that were measured were crackingat 120 percent elongation, percent change in tensile strength (TS) andpercent change in elongation at break (EL), in accordance with theVW3334 Seal Swell Test requirements. The results are shown in Table II.

                  TABLE II                                                        ______________________________________                                                                           ppm N                                      Example    TS     EL         Cracks                                                                              (Calc)                                     ______________________________________                                        10         -14    -17        No    978                                        11         -37    -33        Yes   1194                                       12         -35    -32        Yes   1590                                       13         -35    -33        Yes   2118                                       14         10     02         No    600                                        15         10     03         No    762                                        16         -01    -08        No    972                                        17         -34    -32        Yes   1284                                       18         -01    -05        No    612                                        19         02     -05        No    720                                        20         -26    -20        No    930                                        21         -42    -34        No    1212                                       22         -10    -16        No    462                                        23         -29    -28        No    606                                        24         -33    -28        Yes   738                                        25         -35    -30        Yes   1026                                       26         01     -03        No    306                                        27         03     -03        No    366                                        28         -02    -05        No    456                                        29         -13    -17        No    624                                        30         04     -01        No    294                                        31         -02    -06        No    438                                        32         -10    -12        No    492                                        33         -28    -26        No    582                                        B          -03    -03        No    546                                        C          -09    -13        No    648                                        D          -17    -18        No    876                                        E          01     -06        No    186                                        F          -01    -05        No    240                                        G          -07    -13        No    330                                        H          -14    -19        No    408                                        ______________________________________                                         These polysuccinimides also import advantageous fluidity modifying            properties                                                               

                  TABLE III                                                       ______________________________________                                        VISCOSITY INDEX FOR POLYSUCCINIMIDES                                          Example                                                                              Conc.    V.I. In Exxon 100N                                                                          V.I. In Exxon 600N                              ______________________________________                                        26     10       154           108                                             27     10       136           110                                             28     10       149           118                                             29     10       151           119                                             30     10       153           116                                             31     10       147           106                                             32     10       153           114                                             33     10       169           116                                             ______________________________________                                    

In contrast the V.I. for the same examples as 26-33 except that theconventional thermal PIBSA was used is shown in the following table.

                  TABLE IV                                                        ______________________________________                                        V.I. DATA FOR CONVENTIONAL SUCCINIMIDES                                       Example  Conc.   V.I. In Exxon 100N                                                                          V.I. In Exxon 600N                             ______________________________________                                        bis DETA 10      140           105                                            bis TETA 10      133            99                                            bis TEPA 10      128           103                                            bis HPA  10      141           110                                            EC bis   10      129            99                                            DETA                                                                          EC bis   10      123           102                                            TETA                                                                          EC bis   10      124           103                                            TEPA                                                                          EC bis HPA                                                                             10      133           105                                            ______________________________________                                    

These data show that the V.I. is greater for the polysuccinimides of thepresent invention compared to the conventional succinimides.

While the present invention has been described with reference tospecific embodiments, this application is intended to cover thosevarious changes and substitutions that may be made by those skilled inthe art without departing from the spirit and scope of the appendedclaims.

What is claimed is:
 1. A copolymer of an unsaturated acidic reactant anda high molecular weight olefin, wherein the copolymer has a ratio ofanhydride groups to hydrocarbon groups of between 1.3 and 2.0, whereinthe olefin is selected from the group consisting of alpha olefin andalkylvinylidene olefin, wherein the olefin has an average molecularweight of from 500 to 5000, and wherein the olefin has a sufficientnumber of carbon atoms such that the resulting copolymer is soluble inlubricating oil.
 2. A copolymer according to claim 1 wherein theunsaturated acidic reactant is of the formula: ##STR11## wherein X andX' are each independently selected from the group consisting of --OH,--Cl, --O-- lower alkyl and when taken together, X and X' are --O--. 3.A copolymer according to claim 2 wherein the acidic reactant comprisesmaleic anhydride.
 4. A copolymer according to claim 1 wherein the highmolecular weight olefin is a high molecular weight alkylvinylideneolefin having at least 1 branch per 2 carbon atoms along the chain.
 5. Acopolymer according to claim 1 wherein the olefin has an averagemolecular weight of from 900 to
 2500. 6. A copolymer according to claim4 wherein the olefin is polyisobutene.
 7. A copolymer according to claim6 wherein the alkylvinylidene isomer is methylvinylidene.
 8. A copolymeraccording to claim 1 wherein the copolymer has the formula: ##STR12##wherein n is 1 or greater; and wherein either:(1) R₁ and R₂ are hydrogenand one of R₃ and R₄ is lower alkyl and the other is high molecularweight polyalkyl, or (2) R₃ and R₄ are hydrogen and one of R₁ and R₂ islower alkyl and the other is high molecular weight polyalkyl; andwherein x and y are 1 or greater, such that the sum of x is at least 1.3times the sum of y for the total mixture.
 9. A copolymer according toclaim 8 wherein the high molecular weight polyalkyl comprises apolyisobutyl group of at least 50 carbon atoms.
 10. A copolymeraccording to claim 9 wherein the lower alkyl is methyl.
 11. A copolymeraccording to claim 1 prepared by the process which comprises reacting ahigh molecular weight olefin with an unsaturated acidic reactant in thepresence of a free radical initiator.